Agatized Promicroceras Ammonite Fossils - England

This is a very beautiful multiple Promicroceras planicosta ammonite fossil from the Lyme Regis region of England which has been agatized. It's almost translucent and has been nicely prepared so that it displays very nicely in a slab of limestone. The base of the limestone has been cut flat so it displays nicely without the need for a display stand.

Ammonites were predatory mollusks that resembled a squid with a shell. These cephalopods had eyes, tentacles, and spiral shells. They are more closely related to a living octopus, though the shells resemble that of a nautilus. Ammonites appeared in the fossil record about 240 million years ago and they barely survived several major extinction events. The last lineages disappeared 65 million years ago at the end of the Cretaceous.